Sound waves used to separate microplastics from laundry wastewater newatlas.com

First of all, scientists have already developed filters that help to remove microplastic fibers from the wastewater that drains out of washing machines.
With these limitations in mind, researchers at Japan's Shinshu University have designed what's known as a bulk acoustic wave (BAW) system.
It starts with a central stream of microplastic-fiber-laden wastewater, that forks into three separate channels.
Just upstream of the forking point, a piezoelectric device is used to apply acoustic waves from either side of the central stream, creating a standing acoustic wave in its middle.
Source: Shinshu University via EurekAlert